Dry desulfurization, also known as dry scrubbing or dry flue gas desulfurization (FGD), is a method used to remove sulfur dioxide (SO2) from flue gases emitted by industrial processes or power plants without the use of a liquid absorbent.

The dry desulfurization process typically involves the following steps:

1. Injection of Sorbent: A dry sorbent, such as hydrated lime (calcium hydroxide), sodium bicarbonate, or activated carbon, is injected into the flue gas stream. The sorbent particles react with the sulfur dioxide to form solid byproducts, such as calcium sulfite or calcium sulfate, which are captured in the filter or collection system.

2. Contact and Reaction: The sorbent particles come in contact with the flue gas, allowing for the chemical reaction to occur. The reaction between the sorbent and sulfur dioxide typically takes place at high temperatures.

3. Filtration or Collection: The flue gas, now with reduced sulfur dioxide content, passes through a filtration or collection system to capture the solid byproducts formed during the reaction. This can be done using fabric filters, electrostatic precipitators, or other particulate collection devices.

4. Disposal or Utilization of Solid Byproducts: The captured solid byproducts, such as calcium sulfite or calcium sulfate, can be disposed of or further processed for utilization in various applications, such as construction materials.

Dry desulfurization offers several advantages over wet scrubbing methods, including lower water consumption, reduced wastewater treatment requirements, and potentially lower operating costs. However, it may have lower efficiency in sulfur dioxide removal compared to wet scrubbing methods, especially for high sulfur content fuels.